x Contents
7.11.1 Rings 7-39
7.11.2 Elementary Properties of a Ring 7-41
7.11.3 Polynomial Ring 7-42
7.11.4 Morphism of Rings 7-43
7.11.5 Boolean Ring 7-43
7.12 Ring, Subring and Ideals 7-44
7.12.1 Ideal 7-46
7.12.2 Quotient Ring or Ring of Residue Classes 7-48
7.13 Integral Domain 7-49
7.14 Field 7-50
Exercises 7-51
8. Ordered Sets and Lattices 8-1
8.1 Introduction 8-2
8.2 Partially Ordered Set 8-2
8.2.1 Linearly Ordered or Totally Ordered Set 8-3
8.3 Product of Two Posets 8-3
8.4 Hasse Diagram 8-4
8.5 Lexicographic Ordering 8-8
8.6 Upper And Lower Bounds 8-9
8.6.1 Extremal Elements of Partially Ordered Sets 8-10
8.6.2 Least Upper Bound or Supremum 8-11
8.6.3 Greatest Lower Bound or Infimum 8-12
8.7 Dual of a Poset 8-13 ...